The overall goal is to understand, at the cellular level, how the nervous system identifies and processes olfactory input. The main olfactory system is the prime chemosensory detection system in mammals. The primary sensory cells utilize a large family of odor receptors to detect an enormous and varied set of ligands. At least some discrimination must occur at this level as well, but functions such as mixture recognition, concentration or intensity coding, and adaptation are likely shared with higher order neural circuits in the olfactory bulb. One unusual characteristic of the olfactory bulb is the continuous proliferation of new interneurons which must be integrated into existing neural circuits. We will investigate the properties of these adult born neurons and determine their hypothesized role in olfactory discrimination and learning. This study has two aims. Aim 1. Determine how elimination of new interneurons in the adult olfactory bulb alters the anatomy and physiological output of the bulb. Aim 2. Altering olfactory neurogenesis in the adult olfactory bulb effects memory-dependent behaviors: maternal - pup behavior. We aim to address these issues by drastically reducing or eliminating the population of new-born stem cells, migrating from the subventricular zone (SVZ) to the main olfactory bulb (MOB), with x-ray irradiation of the SVZ. We will test the hypotheses by anatomical, histological, and electrophysiological measures. In addition, we will perform behavioral examinations of maternal behavior and pup development to address the functional cost of reduced neurogenesis. Little is known about the specific synaptic and cellular mechanisms by which new-born neurons can modify neuronal circuit activity, especially in the olfactory bulb. Even less is known about the role of this neurogenesis in mammalian behavior. By understanding how adult born neurons integrate and function within the adult nervous system, we can development therapies to combat neuronal loss, such as in the cases of Parkinson's and Alzheimer's diseases, spinal cord injury, and stroke.